Panic latch



2 Sheets-Sheet l w. CLIFTON, JR

PANIC LATCH -F I 6. I.

Se t. 3, 1957 Filed on. 20, 1955 INVENTOR WALTER L. CLIFTON JR.

BY W) Z ATTORNEYS w. L. CLIFTON, JR

Sept. 3, 1957 PANIC LATCH 2 Sheets-Sheet 2 ATTORNEYS R 7 4 J 4/ a w 1 1m n F I 6 F Z' c F L V m fl r. a, m w A 7; w; f M 5 a 8 z X 0 H A 25 Z Wl 1 United States atent O PANIC LATCH Walter L. Clifton, In, Atlanta,Ga., assignor, by mesne assignments, to American Art Metals Company,

Atlanta, Ga., a corporation of Delaware Application October 20, 1953,Serial No. 387,182

3 Claims. (Cl. 29221) tuating lever or bar extending across the width ofthe door which, when depressed, operates a latch actuating mechanism tounlatch the door and permit it to swing outwardly. Heretofore, it hasbeen the practice to use a positive linkage system mounted at the freeor unhinged side of the door. Such a positive linkage systemnecessitates the use of a number of moving parts and is frequently ofcomplicated structure and difficult to main tain in proper workingcondition. Often such actuating mechanisms have been made to depend uponthe force of gravity acting upon the entire mechanism for returning themechanism to the latched position. Inasmuch as there is a positivelinkage between the parts of the actuating mechanism, jamming of anypart is liable to prevent proper operation of such latching mechanisms.It is imperative in panic doors and the like that there be completereliability of operation at all times and under all conditions.

Other latch actuating mechanisms of this type have replaced the positivelinkage between the latch and the actuating mechanism with meshing gearsegments, the latch members having gear segments formed thereon whichmesh with a gear segment linked to the actuating rods.

In all such latch actuating mechanisms the necessarily complicatedlinkages have failed to give the ease and rapidity of operation which isan essential in this particular type of arrangement.

Accordingly, it is one object of this invention to provide a latchactuating mechanism for panic doors which operates smoothly and rapidlyat all times with a minimum of effort on the part of the operator, andwhich is completely reliable in its operation.

It is another object of this invention to provide a latch actuatingmechanism having a minimum of moving parts, thus greatly decreasing thelikelihood of improper operation.

A further object of this invention is to provide a latch actuatingmechanism wherein the moving parts are operatively engageable with eachother but are not positively linked together, thus greatly simplifyingrepair and maintenance and replacement of parts.

A still further object of this invention is to provide a latch actuatingmechanism for use with a panic latch having means for opening the panicdoor from the outside.

It is still a further object of this invention to provide a latchactuating mechanism having means for retaining the mechanism in itsunlatched position.

h In accomplishing these objects I provide a latch actuating mechanismfor use in panic doors which is contained in a casing received in thefree end of the door and which is actuated by pressure on a barextending across the width of the door. Vertically movable actuatingrods contained in the casing are operatively engaged by this bar and aremoved toward the unlatched position when the bar is depressed.Individual latches are pivotally mounted at the upper and lower ends ofthe casing, these latches being engageable with slots provided in thedoor frame adjacent the latches. A pivotally mounted lever, such as abell crank lever, is disposed adjacent each latch, each lever beingpositively engaged by one of the actuating rods during the upwardmovement of the rod toward the unlatched position. The bell crank leversare thereby caused to pivot about their respective pivot points, and anarm of each bell crank lever engages an arm of its corresponding latchand pivots the latch out of engagement with its socket in the doorframe. 7

Further objectsand advantages of the invention will become apparent fromthe following description taken in conjunction with the drawings inwhich:

' Fig. 1 is a plan view of a panic door embodying the present invention;

Fig. 2 is an elevation view of the panic door taken along the line 22 ofFig. 1 and showing the actuating mechanism which constitutes thisinvention;

Fig. 3 is a view taken along the line 3-3 of Fig. 2;

Fig. 4 is a view taken along the line 44 of Fig. 2;

Fig. 5 is a view taken along the line 5-5 of Fig. 2;

Fig. 6 is a View taken along the line 6-6 of Fig. 2.

Referring now to the drawings and more particularly to Figs. l-5, thereis shown a door frame 11 having latchaccommodating slots 12 and 13 inthe upper and lower transverse portions of the frame. Door 14 having apivoted end 15 and a free end 16 is pivotally mounted within the doorframe 11 and is free to swing outwardly with respect thereto. In theembodiment shown in the drawings the door and door frame are both madeof metal; however, it will be understood that both the door and, theframe maybe of any suitable construction and material adequate toaccommodate the latch actuating mechanism of the invention.

At the free end 16 of the door 14 there is formed a hollow casing 17 forthe accommodation of the latch actuating mechanism. At one side of thedoor and across the width thereof extends a horizontal actuating bar 18which is supported at the free end of the door by actuat ing lever 19and at the pivoted end of the door'by idler lever 21. Levers 19 and 21are pivotally mounted in yokes 2,2 and 23 which are rigidly mounted onthe door slightly below the midpoint of the height thereof so thatactuating arm 13 is readily accessible to the operator. Actuating lever19 has an actuating arm 24 integral therewith and extending into thecasing 17, as best seen in Fig. 2, for operative engagement with theactuating mechanism in a manner which will be explained hereinafter. Inthe embodiment shown actuating arm 24 is substantially perpendicular tothe lever 19.

At the upper end of casing 17 a latch 2.5 is pivotally mounted by meansof a pin 26 so that it is free to move into and ,out of the casing fordisengagement or engagement with upper slot 12 in the door frame. Latch25 has an arm 27 extending downwardly from the pivot 26, as best seen inFig. 2. In a like manner at the lower end of casing 17 a latch 28 ispivotally mounted by means of pin 29 so that it is free to move into andout of the casing for disengagement or engagement with lower slot 13 inthe door frame. Latch 28 has an arm 31 extending upwardly from the pivot29. Both latches 25 and 28 are spring-biased into a normally latchedposition. v

The latch actuating mechanism for controlling movement of latches 25 and28 upon operation of the actuating bar- 18 comprises a G-yoke 32 whichis'rigidly attached to upper and lower actuating rods 33 and 34, 'C-yoke32 being disposed substantially midway of the vertical height of thedoor. Brackets 35, 35 are mounted within the casing and act to restrainmovement of rods 33-and 34 in any direction except the vertical.Inasmuch as rods 33 and 34 are rigidly attached to'C-yoke 32, yoke 32 islikewise restrained from movement in any direction except the vertical.vertical direction with respect to the wall of the casing adjacentmounting yoke 22. Slot 36 in the lower portion of yoke 32 accommodatesactuating arm 24, as best seen in Fig. 2, sothat movement of arm 24about pivot point 20 causes movement of yoke 32 in a vertical direction.

At the upper end of rod 33 is mounted a drag angle 37, and'at the lowerend of rod 34 is mounted a drag angle 38. Mounted Within the casingbelow latch 25 is a bell crank lever 39 which is pivoted on a pin 41.Bell crank lever 39 has a long arm 42 which engages arm 27 of latch 25,and a short arm 43 which extends into a hole or slot 44 in drag angle37. In a like manner at the lower end of the casing 17 a bell cranklever 45 is pivoted on pin 46. Bell crank lever 45 has a long arm 47which engages arm 31 of latch 28 and a short arm 48 which projects intoa hole or slot 49 in drag angle 38.

When actuating bar 18 is depressed, it pivots about pivot point 20 andactuating arm 24. is pivoted in a counterclockwise direction as viewedin Fig. 2. Arm 24 bears against the upper end of slot 36 in yoke 32 andmoves yoke 32 upwardly. This upward movement of yoke 32 causes upwardmovement of rods 33 and 34 and consequently of drag angles 37 and 38.Drag angle 37.

operatively engages upper bell crank lever 39 and pivots the bell cranklever in a counterclockwise direction due to the projection of arm 43 ofthe bell crank lever into the hole or slot 44 of the drag angle. Arm 42of bell crank lever 39 bearsagainst arm 27 of latch 25, and pivots latch25 in a clockwise direction, out of engagement with slot 12.Simultaneously, drag angle 38, at the lower end of the latchingmechanism, through operative engagement with bell crank lever 45, pivotslever 45 in a clockwire direction as viewed in Fig. 2 causing arm 47 ofcrank lever 45 to pivotally move latch 28 in a counterclockwisedirection out of engagement with slot 13. Since latches 25 and 28 aredisengaged from their respective slots 12 and 13, door 14 is now free toswing with respect to door frame 11.

The unlatching mechanism is normally urged to a downward position by thecombined eflfects of gravity and springs 50 and 52. Spring 50 ispositioned between the uppermost surface of the C-yoke 32 and the lowersurface of the guide 35 disposed nearest to that surface. Spring 52 ispositioned between the uppermost surface of the lower drag angle 38 andthe lowermost surface of the guide 35 disposed nearest that surface. Itcan be seen that both springs 50 and 52 cooperate with the force ofgravity to normally urge. the operating mechanism, including the G-yoke32, the rods 33 and 34 and the drag angles 37 and 38, in a downwarddirection, permitting the latches 25 and 28 to assume a normally latchedposition.

As long as pressure is maintained on the operating handle 18 to move thelever 24 in a counterclockwise direction about its pivot point 20, thelatch actuating mechanism is maintained in an actuated position tothereby move the latches 25 and 28 to unlatched position. However, assoon as force is released from handle 18, the springs 50 and 52, incooperation with the force of gravity, force the latch actuatingmechanism in a downward direction to the position shown in Fig. 2 whichpermits the spring-biased latches 25 and 28 to return to their normallylatched position, in which they engage the respective slots 12 and 13.

A suitably constructed key operated cam mechanism is provided to permitthe latch actuating mechanism to Yoke 32 is slidably movable in a bemoved to an unlatched position from the outside of the door. Anexemplary construction of this nature is illustrated at 54 in Fig. 2.

Still another feature of the construction is an arrangement whichpermits the latch actuating mechanism, including the yoke 32, the rods33 and 34, and the drag angles 37 and 38 to be maintained continuouslyin an elevated position to thereby maintain the latches 25 and 28disengaged from their respective slots 12 and 13. To accomplish thisobjective, a dogging-down cam 66, mounted on a shaft 68, is provided, aswill best be seen in Fig. 6. The cam 66 is operable from the insidesurface of the door by means of a wrench, such asan Allen wrench, andthe cam is engageable with an abutment 70 which extends laterally fromthe upper portion of the C-yoke 32 to cam the yoke 32 in an upwarddirection. When rotated degrees from the position shown in Figs. 2 and6, the outer end of the cam 66 engages the notch 72 in the abutment 70in such manner as to maintain the C-yoke in an elevated position. Theyoke 32 is slotted at 67 to permit the yoke to move upwardly withrespect to the shaft 68 of cam 66. The bell cranks 39 and 45 areactuated in the same manner as though the lever 19 were manually pusheddownwardly to move the latches 25 and 28 to unlatched position. When thecam 66 engages the notch 72, the latch actuating mechanism is maintainedin its elevated position for as long as desired until the cam is rotatedaway from the position in which it engages the notch 72 of the abutment70. This provides a convenient means for maintaining the latches 25 and28 in an unlatched condition for any desired length of time.

It can be seen that this invention provides a panic latch actuatingmechanism which is simple in construction and completely reliable inoperation. The mechanism has a minimum of moving parts, and theoperating relation between the operating mechanism and the latches is sosimple that it decreases the chances of improper operation andsimplifies the repair and maintenance of the mechanism. Furthermore,there is provided in cooperation with the latch actuating mechanism aCOHStruction which permits the latches to be moved to unlatched positionfrom outside the door. Means are also provided for maintaining thelatches in unlatched condition for any desired length of time by meansof a wrench-operated dogging-down cam which is operated from inside thedoor. The mechanism is so constructed that the actuating, dogging-downand unlocking mechanisms are concentrated at or near the vertical centerline of the assembly, and so that the weight of all the verticallymoving parts tends to latch the door, thereby augmenting the effect ofthe springs 50 and 52.

While there has been shown and described a particular embodiment of theinvention, it will be obvious to those skilled in the art that variouschanges and modifications can be made therein without departing from theinvention, and therefore it is aimed in the appended claims to cover allsuch changes and modifications as fall within the true spirit and scopeof the invention.

What I claim as my invention is:

1. In combination with a door mounted for swinging movement about avertical pivot and having upper and lower horizontal edges and avertical outer edge extending between said upper and lower edges, apanic latch assembly comprising retractable latch members normallyprojecting to the outer side of the door, a projection on said upperlatch member extending downwardly from said upper latch member towardthe outer side of the door, a projection on said lower latch memberextending upwardly from said lower latch member toward the outer side ofthe door, a movable pusher abutting against the downwardly extendingprojection of said upper latch member and movable against saidprojection to pivot said latch member toward the inner side of the doorto retract the latch member, a movable pusher member abutting againstthe upwardly extending projection of the lower latch member and movableagainst said projection to pivot said lower latch member toward theinner side of the door to retract said lower latch member, and anactuating rod assembly supported by said door for upward and downwardmovement with respect to said vertical outer door edge, said rodassembly including means at the upper and lower ends thereof engagingsaid pushers to move both of said pushers to retract both of said latchmembers when said rod assembly is moved upwardly, each latch memberbeing pivotally movable toward the inner side of said door against theaction of said spring means and independently of the pusher associatedtherewith and away from contact with said pusher whereby, when said doorswings inwardly, each latch member may be depressed to a retractedposition without lifting said rod assembly upwardly, a biasing springengaging said rod assembly to bias said rod assembly downwardly tonormally maintain said pushers in a position where they do not retractsaid latch members,

6 and means connected to said rod assembly to move said rod assemblyupwardly against the force exerted by said biasing spring.

2. A panic latch assembly according to claim 1 wherein each pusher is apivotally mounted bell crank having one arm abutting against the latchprojecting associated therewith and another arm engaged by the rodassembly means associated therewith, said bell crank being mounted forpivotal movement in a direction such that said bell crank arm abuttingsaid latch projection can push said latch projection toward the innerside of said door to retract the latch.

3. A panic latch assembly according to claim 2 wherein each bell crankarm engaged by the rod assembly means associated therewith is looselyreceived within a horizontal opening in a vertical member forming a partof said rod assembly means.

References Cited in the file of this patent UNITED STATES PATENTS858,479 Smith July 2, 1907 1,117,457 Smith Nov. 17, 1914 1,518,187 DyerDec. 9, 1924 1,708,078 Bolles Apr. 9, 1929 1,721,489 Prinzler July 16,1929 FOREIGN PATENTS 67,555 Germany Mar. 13, 1893

